We are investigating mechanisms by which prostaglandins produce changes in pulmonary function and pulmonary circulation in dogs and in normal and pulmonary disease subjects. We infused arachidonic acid into the superior vena cava of anesthetized, paralyzed and artificially ventilated dogs. Measurements of resistance of the respiratory system, dynamic compliance, pressures in the pulmonary artery and aorta, cardiac output, and serum concentrations of the products of arachidonic acid metabolism (e.g. PGF and E and their metabolite, prostacyclin and thromboxane) from the pulmonary artery and aorta, are performed. In addition, morphologic studies include gross examination of the lungs and tantalum bronchography. In normal or pulmonary disease subjects, pulmonary function and other physiologic studies are correlated to endogenous plasma concentrations of arachidonic acid and prostaglandin E series and F2 alpha, 6-keto-F1 alpha and thromboxane B2. In other studies we are investigating the relationships of altered prostaglandin metabolism and abnormal platelet and membrane function.